Find all angles θ between 0° and 180° satisfying the given equation. Round your answer to one decimal place. (Enter your answers as a comma-separated list.) cos(θ) = 7/9

Question

I don’t get what it means by comma separated list?

Answer 1

cosT = 7/9

T = cos^-1(7/9)

The angle = about 38.94 degrees

use a calculator with an inverse cosine function

there's only one answer

had there been 2 or more answers, you'd list them with a comma between each.

7/9= .777...

cos30 = sqr3/2 = 1.732/2 = .866...

.866 is a little more than .777...so T is a little more than 30 degrees. 38.94 looks about right

cos45 = sqr2/2 = 1.414/2 =.707

T is somewhere between 30 and 45 degrees, such as 38.94 degrees